Chapters:
00:00 Myth #1: Carbs make us fat
00:44 Myth #2: Hormones have a big effect on fat loss
01:44 Myth #3: It takes 3500kcal to lose 1lb of fat
02:11 Myth #4: Weight maintenance = energy maintenance
03:51 Myth #5: Some people just can’t lose fat
04:26 Myth #6: Excessive dieting causes metabolic damage
05:19 Myth #7: You have a genetic body fat set-point
07:02 Outro
Transcript:
Fat loss myth #1: Carbs make us fat. Reality: Calories make us fat. We have numerous long term studies showing that low fat and low carb diets are equally effective for weight and fat loss. When you equate for the total energy content and the total protein content of the diet, low carb and low fat diets are equally effective for fat loss. “But Menno, isn’t insulin a fat storage hormone?” It’s a little bit more complex than that, but yes, insulin is a storage hormone. The thing is, insulin cannot store what isn’t there. So insulin is only net fat promoting in energy surplus. In the end, it all comes back to energy balance. The laws of thermodynamics always apply.
Fat loss myth #2: Hormones have a big effect on fat loss. The reality is that various hormones can have significant effects on our appetite. Independent of our energy intake and our calorie intake though, the effects of hormones are marginal. Hormones can affect our energy expenditure, but even thyroid hormone, which is the master regulating hormone of our metabolism, only has about 5% effect on our resting energy expenditure. In studies, where we look at people on thyroid hormone going from the low end to the upper end of the normal range, so people that don’t have clinical disorders, we see about a 5% difference in resting energy expenditure. So that’s not a lot. In fact, even people that are hypothyroid, so they have a clinical disorder that makes their body produce too little thyroid hormone, when we then give them thyroid hormones we see that they often lose very little fat. They do lose some weight, but it’s mostly water loss because hypothyroidism also causes massive water retention. So overall hormones do affect fat loss, but the effects are quite marginal in most cases.
Fat loss myth #3: It takes 3500 calories to lose a pound of fat. Unfortunately, the idea that it takes 7000 calories to lose a kilo of fat comes with the assumption that you’re losing a certain amount of lean body mass, usually muscle mass. When you actually look at the amount of fat it takes to lose a kilo of pure adipose tissue, which is actual body fat, it’s 8260 calories. So that’s the net energy deficit you actually have to achieve to lose a kilo of fat.
Diet myth #4: Weight maintenance equals energy maintenance. They are not actually the same. Even in the respectable journal “Nutrition Reviews” from Oxford University Press the following image appeared equating weight to energy maintenance. So if you are on your diet, you’re not losing any weight, your weight is completely stable, that does not actually mean that you are at energy maintenance. In sedentary individuals, with all other diet factors controlled, this is practically true. Not theoretically true, but it is practically true. However, for strength trainees it is definitely not always the case. For example, what I often see in my clients is that they lose fat, but they gain muscle, ending up maintaining their weight, and if you’re not tracking their body fat levels separately from their weight you might be mistaken to think that they’re just not losing any fat. And yes, it is absolutely possible to build muscle in energy deficit, there are tons of studies showing this is possible even in trained individuals. The more trained you are, the harder it gets, but it is still possible.
Another common reason for a seeming weight loss plateau is water retention. Many people don’t lose weight completely linearly over time. Instead, it’s more of a stairways pattern where they lose some fat, but they hold water, and therefore their weight remains the same for certain period until they have a so-called “whoosh effect” and that water comes off. And you sometimes see that people’s weight is about the same for about a week, and then they lose a whole kilo or half a kilo out of nowhere, it seems. In reality the fat loss underneath is linear, but the weight loss is stairways. It’s also possible to be in energy deficit and to lose fat, but still retain your weight when you go, for example, on creatine and you hold associated water due to that. So while being in weight maintenance can be a practical way to approximate energy balance, it is not actually a theoretical test of energy balance, and you have to be careful with it.
Fat loss myth #5: Some people just can’t lose fat. Fact: Everyone can lose fat. I’ve never had a client that couldn’t lose fat. It is theoretically impossible. Thermodynamics always apply. If you are an energy deficit your body has to burn some of its own tissues to make up the deficit and fuel its energy expenditure. There is no way around that. So if you are not losing fat the only logical step is that you have to increase energy expenditure or you have to decrease energy intake and you will lose fat 100% guaranteed. The laws of physics demand it.
Fat loss myth #6: Excessive dieting causes metabolic damage. I have extensively researched this with my own research team, and we found no evidence of metabolic damage, even in malnourished populations, in women with anorexia nervosa, in bodybuilders in contest prep, in wrestlers doing very aggressive weight loss practices to make weight, and in the famous Minnesota starvation experiment, where they literally starved people almost to death to see what would happen. In World War II ethics committees were a bit more lenient with what they could study. In all of these cases we found that people’s metabolism could be predicted based on their body composition. So as they lost weight their metabolism slowed down, they had less tissue, there was adaptive form of genesis, but when they regained the weight and their body composition returned back to baseline their metabolism was exactly the same as it was before, indicating there was no permanent metabolic damage that took place, only temporary adaptation.
Fat loss myth #7: You have a genetic body-fat set-point. When you’re dieting it sometimes feels like no matter what we do we just gravitate back towards that same body fat percentage and there’s nothing we can do about it. In reality, there is everything we can do about it, and there is no evidence that we have any genetic set-point. It’s not like we have some number in our brain that makes our body go towards that body fat percentage no matter what we do. In reality, what we see is that we have, what’s sometimes called a settling point. I don’t like the term though, because it’s still implies something beyond our control. The settling point is the cumulative effect of our lifestyle, our energy intake, our food choices, our activity level, all of these things. They set the inputs for our energy expenditure and our energy intake and therefore gradually we gravitate, given those inputs to a certain body fat level. And what we see is that people that go on a diet, meaning a six week period of suffering for the summer, rather than sustainable lifestyle change, and then they go off the diet, they revert back to their previous lifestyle, then, of course, they also revert back to their previous body fat level. So we see very consistently in research that people’s lifestyle factors determine where they end up with their body fat percentage and failure to maintain your leaner body fat percentage is due to a failure of maintaining the lifestyle that got you there in the first place.
Another big factor in people that don’t even lift is that muscle loss during the diet reduces their energy expenditure. So sometimes, when they revert back to their previous lifestyle, they go off the diet, they actually end up in a worse position which is called body fat overshooting, because now they are at the same body fat level or the same weight, but with more fat, and they still haven’t regained that muscle that they lost on the diet. Muscle loss suppresses energy expenditure making it even more difficult to even maintain the previous body composition. That’s why it’s so important to lift weights even when your goal is purely fat loss. I hope this video helps you with your fat loss goals. If you like this type of content, I’d be honored if you’d like and subscribe.